Thread: Help understanding the POI changes with altitude / range finding data / Leica HD-B

For hunting purposes I create drop chart based on 3000 ft alt (typical bushline), 15C , 1010 hPa and 85% rel hum for average for "summer" conditions.
If you change your alt by 1000 ft or so, it makes stuff all difference to your drops - well, not for normal hunting ranges anyway, out to 600 - 800 yards. Further out you need to pay more attention.
For example with 7mmRM running 162 MAX @ 3000fps, then drop at 500 yards = 6.6 moa at 3000ft and 6.7moa at 300ft alt.
At 800 yrds its 15.1 moa at 3000ft vs 15.6moa at 300ft. A 0.5 moa change with 2700ft alt difference. ( this is using the Hornady online ballistics app)
Like @223nut says, you can use any of the on line ballistics packages to model out the impacts. Play around with all variables, not just alt - temp & air pressure etc, and you'll get a very good feel for the magnitude of impacts.
Remember BC is the gift that keeps giving, high bc pills will be less affected